[Elecraft] [K2] K2 Difficulty Fine Adjusting AGC

[Don Wilhelm]

Brian,

A receiver gain problem will usually result in S-meter problems similar 
to what you describe - to get a 50 uV signal to show S-9, the CAL S HI 
value will be far removed from that obtained when you do the adjustment 
with the RF Gain full counterclockwise.
Normally, the S-9 point with a 50 uV input will only be a few numbers 
different than the initial adjustment (i.e. 16 instead of 19 as an 
example- but those numbers are not unusual).

It may be that you have noticed the lack of receive gain, but if you 
have to run the AF Gain up to the 11 o'clock position or more for a 
normal listening level with moderately strong signals, that is one 
indicator that something is amiss.

If the MDS measurement indicates a problem, build the signal generator 
shown in the K2 manual Appendix E and using it to do receiver signal 
tracing (also as detailed in the manual) may be able to identify the 
problem stage or section.

If MDS measurement show adequate receive sensitivity (-133 to -138 dBm), 
then you can look for the problem in the AGC/S-meter section of the K2 
(this is on the Control Board).

It is sufficient to say that your K2 is not acting normally, and the 
problem should be found and corrected.

73,
Don W3FPR


Brian - N5BCN wrote:
> Hi Don,
>
> Thanks for the suggestions.
>
> In reference to Problem 1, all of the testing was done with the antenna
> disconnected and preamp off.  Even so, still having problems differentiating
> much of a sound difference will adjusting AGC Threshold Voltage.  Is this
> perhaps because of the gain problem I'm having that you suggested?
>
> I'll perform the MDS measurements and see where that takes me.
>
> I can't really detect much of a problem on receive.  How would this gain
> problem (between the antenna and product detector) manifest itself in normal
> operation?
>
> Thanks!
>
> 73
>   
>